In this paper,the research work on the distribution of silicon and its effect on the phytoplankton community structure in the lake ecosystem were reviewed and discussed.Results show that:( 1 ) The distribution of DSi (dissolved silica),PBSi (particulate biogenic silica) and BSi (biogenic silica) in sediment in various lakes has become increasingly concerned.The correlations between silicon and its influencing factors ( such as carbon,nitrogen,phosphorus,phytoplankton) need further investigation.(2)Eutrophication,hydrologic management and biodeposition can contribute to silica depletion in various aquatic ecosystems.Silica depletion can cause silicon limitation on the growth of diatoms and other siliceous phytoplankton.The criterion of silicon limitation is still under debate.(3) Silicon limitation can cause phytoplankton shifts from diatoms to nonsiliceous algae,and further cause harmful nonsiliceous algal blooms,such as cyanobacteria bloom in freshwater.Silicon is clearly playing a crucial role in controlling the appearance of such algal blooms,however,it is knowed that nutrient balahce among silicon,carbon,nitrogen and phosphorus is a more impertant controlling factor.(4) Since eutrophication and algal blooms have become the most universal and serious environmental problems of lakes,it is suggested to make efforts in investigating into the mechanism of the impacts of nutrient balance among silicon,carbon,nitrogen and phosphorus on the eutrophication and algal blooms in lake ecosystems.